Stardates: 5221.3, 5221.8--The U.S.S. Enterprise explores beyond the outer fringe of the Galaxy, where mysterious radio emissions are detected from Questar M-17. A field of hyper-gravity from an undetected imploded star causes the Enterprise to accelerate out of control.

The Enterprise becomes trapped in orbit around the collapsed star, along with an ancient alien starship, which is the source of the mysterious radio signals and has been in orbit for more than 300,000,000 years.

Captain Kirk leads a landing party to the alien ship, which was constructed by an insect-like race. The last log entry on the ancient ship states that the aliens destroyed their ship rather than let a malevolent life form escape from the magnetic field of the dead star.

When the landing party beams back to the Enterprise, a non-corporeal magnetic energy entity also transports aboard, and takes over the ship's systems.

Rather than let the energy entity escape into the Galaxy, Captain Kirk steers the Enterprise toward the dead star, and the entity leaves the ship and returns to the star's magnetic field, before the Enterprise uses a warp slingshot maneuver to escape the star's gravity. The Enterprise then continues its star-charting mission beyond the farthest star of the Galaxy.

original airdate--September 08,1973

Alien Races: Edoan

Starships: U.S.S. Enterprise NCC-1701

Goofs: Between different shots, Sulu changes from sitting next to Lt. Arex to sitting next to a human.

The lower half of Scotty's body from the waist down isn't drawn and painted in while he's on the bridge.

After having beamed on to the alien derelict, the force field surrounding Kirk is part way off him as if the animator didn't center Kirk into the outline.